French GP: Renault technical preview

Renault Tech File: Magny-Cours
Downforce
We run medium to high levels of downforce at Magny-Cours in order to get
improve braking and traction, as well as grip in the medium speed
corners. While it might seem tempting to reduce wing levels to...

Renault Tech File: Magny-Cours

Downforce

We run medium to high levels of downforce at Magny-Cours in order to get
improve braking and traction, as well as grip in the medium speed
corners. While it might seem tempting to reduce wing levels to improve
top speed to try and overtake competitors on the run to turn 5, this is
actually counter-productive: reducing wing costs the drivers speed in
turn 3, reducing their exit speeds and having little impact on the speed
at the end of the straight.

Suspension

The circuit features an exceptionally smooth surface, meaning we can run
the cars with very low ride heights, and stiff suspension. Stiff
suspension offers benefits in terms of aerodynamic performance, and the
change of direction in the quick chicanes at turns 6/7 and 11/12. The car
may end up a little nervous in these sections, but this does not cost
time as both are followed by braking zones and slow corners. In terms of
suspension settings, we must nevertheless find the right balance between
stiffness for the higher speed sections, and mechanical grip for the slow
corners.

Reliability

Magny-Cours presents few unusual reliability challenges for the cars, but
the major one comes at the final chicane with its very high kerbs. The
quickest line involves bouncing over both kerbs, but brings with it the
associated risks of over-revving the engine and overloading the
transmission. While the drivers will always use the optimum line in
qualifying to achieve the fastest lap-time, they may alter this slightly
for the race to look after the mechanicals of the car.

Track temperature

The track surface at Magny-Cours is notorious for its temperature
sensitivity. A variation in its exposure to sunlight can have a large
effect on the track temperatures, and something as seemingly innocuous as
a passing cloud could take a tyre compound out of its optimum operating
window. This is something we try and counter in our tyre choice, and we
pick the most suitable compound for the predicted conditions. In general,
rising temperatures will make the car oversteer more, and the evolution
of track temperature is something we track throughout the weekend.

Engine torque

Magny-Cours is a circuit where engine torque plays a prominent role. We
need strong levels of torque to launch the cars out of the numerous slow
corners, but also good torque control at higher revs. In turn 3, and also
at the two quick chicanes, the drivers go back to full throttle while the
car is turning and under high aerodynamic loads. Power delivery must
therefore be as smooth as possible to avoid unsettling the car balance.
This will be a less of a factor with the V8 engines than with the V10
generation, owing to reduced levels of torque.

Gearing

Gear ratios at Magny-Cours tend to be shortly-spaced in order to optimise
the car's acceleration from slow speeds. This means our attention is
focused primarily on the 0-250 kph range without too many worries about
top speeds. This is because the primary passing opportunity on the
circuit is at the end of the back straight, which is preceded by an
'aero-dominant' corner where following another closely car is
difficult -- which makes it hard to use any straightline speed
advantage on the exit. However, the exception to this rule can come on
the first lap where gaps between cars have not stabilised -- and it is
still possible to pass for position.

Control systems

The control systems are important in two main areas at Magny-Cours:
firstly, for controlling rear tyre wear; and secondly, to avoid
over-revving at the final chicane when the cars leap into the air and
leave the rear wheels spinning freely. However, these tasks are part of
our 'normal' weekend work and do not present a significant additional
challenge.

Extra Motif-ation at Magny-Cours

This weekend's Grand Prix will be the second time in a week that France
and Italy have faced off with a world championship at stake. At
Magny-Cours, 'les bleus' will be facing up to the challenge of the
Scuderia Ferrari -- and they will be getting a little helping hand
from a new livery, from the pen of Korean designer B-S Choi.

A contemporary fashion designer and celebrity in his native Korea, Choi
has drawn inspiration from the parallels between the sweeping, blue
curves of the R26 race-car and the dynamism of the ocean. The white
livery symbolises a shark, with its sharp teeth, glaring eyes and
muscular form scything through the 'grand bleu' as the Renault
race-cars hopes to do through the F1 field on Sunday afternoon. After the
unique tiger and keris designs brought success in Silverstone and
Montreal, we hope to make it a hat-trick in Many-Cours!